In low volume irrigation of horticulture and agricultural crops, known devices are mainly drippers and spray devices which are fixed along an irrigation tube that lies on the ground. Acceptable irrigation tubes are made of rigid, semi-rigid or flexible plastic. In the dripper device field there are known different and varied types of drip openings/devices that are fixed along the irrigation tube at regular intervals. In the drippers known today the output of water passing through each drip unit along the tube is uniform and dependent upon the water pressure in the tube. In the known devices regulation of dripping rate can be done only by uniform regulation of dripping rates along the tube, so that individual and independent regulation of each drip unit is not possible.
There are devices for regulation of water flow in the irrigation tube but they are not specific to each dripping point but to the tube as a whole (see e.g., Israeli patent 50650).
An object of the present invention is to provide a dripper device in which the amount of water discharged per time unit is easily and simply adjusted to meet gardening requirements at each and every drip device. Therefore in horticulture and agricultural crops it is possible to provide each and every sit and plant with different amounts of water per time unit according to the individual plant need. The individual dripping differs in rate at each site and leads to a more efficient utilization of a given amount of water, resulting in water savings.
Known today are also low volume spray units connected to or inserted in an irrigation tube, e.g., U.S. Pat. No. 4,123,006. In this U.S. patent it is not possible to adjust sector, height and distance characteristics for each spray unit. Moreover, the spray device cannot be used as a dripper.